Magnetic Recording Devices Using Virtual Side Shields for Improved Areal Density Capability

ABSTRACT

Embodiments of the present disclosure generally relate to a magnetic media drive employing a magnetic recording device. The magnetic recording device comprises a trailing gap disposed adjacent to a first surface of a main pole, a first side gap disposed adjacent to a second surface of the main pole, a second side gap disposed adjacent to a third surface of the main pole, and a leading gap disposed adjacent to a fourth surface of the main pole. A side shield surrounds the main pole and comprises a heavy metal first layer and a magnetic second layer. The first layer surrounds the first, second, and third surfaces of the main pole, or the second, third, and fourth surfaces of the main pole. The second layer surrounds the second and third surfaces of the main pole, and may further surround the fourth surface of the main pole.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 17/039,840, filed Sep. 30, 2020, which application is adivisional of co-pending U.S. patent application Ser. No. 16/564,704,filed Sep. 9, 2019, each of which is herein incorporated by reference.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

Embodiments of the present disclosure generally relate to data storagedevices, and more specifically, to a magnetic media drive employing amagnetic recording device.

Description of the Related Art

Over the past few years, energy assisted magnetic recording (EAMR) hasbeen studied as a recording method to improve the areal density of amagnetic read/write device, such as a hard disk drive (HDD). EAMRenabled magnetic recording devices utilize an EAMR stack including atleast one magnetic layer, such as a spin torque layer (STL), that ismagnetized by a bias current during operation. The EAMR stack is oftendisposed between the trailing shield and the main pole to improve writefield and/or field gradient, leading to better areal density capability(ADC).

Typical EAMR enabled magnetic recording devices further comprise a mainpole surrounded by one or more side shields. However, due to the chargescoming off of the main pole when a write current is applied to write toa media, adjacent tracks on the media may be erased. As such, the sideshields are used for reducing the erasure in adjacent tracks and forfurther improving the tracks per inch (TPI) performance. On the otherhand, the side shields cause magnetic shunting in the side gaps of themagnetic recording device, reducing the bits per inch (BPI) of themagnetic recording devices.

Therefore, there is a need in the art for an improved magnetic recordingdevice design to reduce the erasure in adjacent tracks and to preventshunting of the magnetic flux in the main pole.

SUMMARY OF THE DISCLOSURE

Embodiments of the present disclosure generally relate to a magneticmedia drive employing a magnetic recording device. The magneticrecording device comprises a trailing gap disposed adjacent to a firstsurface of a main pole, a first side gap disposed adjacent to a secondsurface of the main pole, a second side gap disposed adjacent to a thirdsurface of the main pole, and a leading gap disposed adjacent to afourth surface of the main pole. A side shield surrounds the main poleand comprises a heavy metal first layer and a magnetic second layer. Thefirst layer surrounds the first, second, and third surfaces of the mainpole, or the second, third, and fourth surfaces of the main pole. Thesecond layer surrounds the second and third surfaces of the main pole,and may further surround the fourth surface of the main pole.

In one embodiment, a magnetic recording device comprises a main polehaving a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, and a sideshield surrounding one or more of the first surface, the second surface,the third surface, and the fourth surface of the main pole, including atleast one of the second surface and the third surface, wherein the sideshield comprises a first layer comprising a heavy metal material, and asecond layer comprising a magnetic material, wherein the second layerhas a greater thickness than the first layer, and wherein the firstlayer and the second layer have a total thickness between about 2 nm toabout 20 nm.

In another embodiment, a magnetic recording device comprises a main polehaving a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, a trailingshield disposed adjacent to the trailing gap, and a side shieldcomprising a first layer surrounding the first surface, the secondsurface, and the third surface of the main pole, and a second layersurrounding the second surface and the third surface of the main pole.

In yet another embodiment, a magnetic recording device comprises a mainpole having a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, a trailingshield disposed adjacent to the trailing gap, one or more side gapsdisposed below the trailing shield and surrounding the second and thirdsurfaces of the main pole, and a side shield surrounding the secondsurface, the third surface, and the fourth surface of the main pole, theside shield comprising a first layer in contact with the one or moreside gaps and a second layer in contact with the first layer, whereinthe side shield is spaced from the trailing shield and the main pole.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 illustrates a disk drive embodying this disclosure.

FIG. 2 is a fragmented, cross-sectional side view through the center ofa read/write head facing a magnetic media, according to one embodiment.

FIG. 3 illustrates an MFS view of a magnetic recording device having avirtual side shield, according to one embodiment.

FIG. 4 illustrates an MFS view of a magnetic recording device having avirtual side shield, according to another embodiment.

FIGS. 5A-5C illustrate MFS views of magnetic recording devices eachhaving a virtual side shield, according to various embodiments.

FIG. 6 illustrates an MFS view of a magnetic recording device having avirtual side shield, according to yet another embodiment.

FIG. 7 illustrates a cross-sectional view of a magnetic recording deviceillustrating the effects of a virtual side shield, according to oneembodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments of the disclosure.However, it should be understood that the disclosure is not limited tospecific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practice thedisclosure. Furthermore, although embodiments of the disclosure mayachieve advantages over other possible solutions and/or over the priorart, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the disclosure. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s). Likewise, reference to“the disclosure” shall not be construed as a generalization of anyinventive subject matter disclosed herein and shall not be considered tobe an element or limitation of the appended claims except whereexplicitly recited in a claim(s).

Embodiments of the present disclosure generally relate to a magneticmedia drive employing a magnetic recording device. The magneticrecording device comprises a trailing gap disposed adjacent to a firstsurface of a main pole, a first side gap disposed adjacent to a secondsurface of the main pole, a second side gap disposed adjacent to a thirdsurface of the main pole, and a leading gap disposed adjacent to afourth surface of the main pole. A side shield surrounds the main poleand comprises a heavy metal first layer and a magnetic second layer. Thefirst layer surrounds the first, second, and third surfaces of the mainpole, or the second, third, and fourth surfaces of the main pole. Thesecond layer surrounds the second and third surfaces of the main pole,and may further surround the fourth surface of the main pole.

FIG. 1 illustrates a disk drive 100 embodying this disclosure. As shown,at least one rotatable magnetic media 112 is supported on a spindle 114and rotated by a disk drive motor 118. The magnetic recording on eachdisk is in the form of any suitable patterns of data tracks, such asannular patterns of concentric data tracks (not shown) on the magneticmedia 112.

At least one slider 113 is positioned near the magnetic media 112, eachslider 113 supporting one or more magnetic head assemblies 121. As themagnetic media rotates, the slider 113 moves radially in and out overthe media surface 122 so that the magnetic head assembly 121 may accessdifferent tracks of the magnetic media 112 where desired data arewritten. Each slider 113 is attached to an actuator arm 119 by way of asuspension 115. The suspension 115 provides a slight spring force whichbiases the slider 113 toward the media surface 122. Each actuator arm119 is attached to an actuator means 127. The actuator means 127 asshown in FIG. 1 may be a voice coil motor (VCM). The VCM includes a coilmovable within a fixed magnetic field, the direction and speed of thecoil movements being controlled by the motor current signals supplied bycontrol unit 129.

During operation of the disk drive 100, the rotation of the magneticmedia 112 generates an air bearing between the slider 113 and the mediasurface 122 which exerts an upward force or lift on the slider 113. Theair bearing thus counter-balances the slight spring force of suspension115 and supports slider 113 off and slightly above the media 112 surfaceby a small, substantially constant spacing during normal operation. TheDC magnetic field generated from the magnetic head assembly 121 enhancesthe write-ability so that the write elements of the magnetic headassemblies 121 may correctly magnetize the data bits in the media 112.

The various components of the disk drive 100 are controlled in operationby control signals generated by control unit 129, such as access controlsignals and internal clock signals. Typically, the control unit 129comprises logic control circuits, storage means, and a microprocessor.The control unit 129 generates control signals to control various systemoperations, such as drive motor control signals on line 123 and headposition and seek control signals on line 128. The control signals online 128 provide the desired current profiles to optimally move andposition slider 113 to the desired data track on media 112. Write andread signals are communicated to and from write and read heads on theassembly 121 by way of recording channel 125.

The above description of a typical magnetic disk storage system and theaccompanying illustration of FIG. 1 are for representation purposesonly. It should be apparent that disk storage systems may contain alarge number of disks and actuators, and each actuator may support anumber of sliders.

FIG. 2 is a fragmented, cross sectional side view through the center ofa read/write head 200 facing the magnetic media 112, according to oneembodiment. The read/write head 200 may correspond to the magnetic headassembly 121 described in FIG. 1. The read/write head 200 includes amedia facing surface (MFS) 212, such as an air bearing surface (ABS), amagnetic write head 210, and a magnetic read head 211, and is mountedsuch that the MFS 212 is facing the magnetic media 112. The read/writehead 200 may be an energy-assisted magnetic recording (EAMR) head. InFIG. 2, the magnetic media 112 moves past the write head 210 in thedirection indicated by the arrow 232 and the read/write head 200 movesin the direction indicated by the arrow 234.

In some embodiments, the magnetic read head 211 is a magnetoresistive(MR) read head that includes an MR sensing element 204 located betweenMR shields S1 and S2. In other embodiments, the magnetic read head 211is a magnetic tunnel junction (MTJ) read head that includes a MTJsensing element 204 located between MR shields S1 and S2. The magneticfields of the adjacent magnetized regions in the magnetic media 112 aredetectable by the MR (or MTJ) sensing element 204 as the recorded bits.

The write head 210 includes a return pole 206, a main pole 220, atrailing shield 240, and a coil 218 that excites the main pole 220. Thecoil 218 may have a “pancake” structure which winds around aback-contact between the main pole 220 and the return pole 206, insteadof a “helical” structure shown in FIG. 2. A trailing gap (not shown) anda leading gap (not shown) may be in contact with the main pole and aleading shield (not shown) may be in contact with the leading gap. Arecording magnetic field is generated from the main pole 220 and thetrailing shield 240 helps making the magnetic field gradient of the mainpole 220 steep. The main pole 220 may be a magnetic material such as anFeCo alloy. The main pole 220 may include a trailing surface 222 whichmay be parallel to a leading surface 236 of the trailing shield 240. Themain pole 220 may be a tapered write pole (TWP) with a trailing edgetaper (TET) configuration. In one embodiment, the main pole 220 has asaturated magnetization (Ms) of 2.4 T and a thickness between about 300nanometers (nm). The main pole 220 may comprise ferromagnetic materials,typically alloys of one or more of Co, Fe and Ni. The trailing shield240 may be a magnetic material such as NiFe alloy. In one embodiment,the trailing shield 240 has an Ms of about 1.2 T to about 1.6 T.

FIG. 3 illustrates an MFS view of a magnetic recording device 300 havinga virtual side shield 310, according to one embodiment. The magneticrecording device 300 may correspond to the magnetic head assembly 121described in FIG. 1 and/or the read/write head 200 described in FIG. 2.The magnetic recording device 300 comprises a main pole 302, a trailingshield 304 disposed above the main pole 302, and an EAMR stack 320disposed between the main pole 302 and the trailing shield 304 in atrailing gap 322. The EAMR stack 320 may be a spin orbital torque (SOT)structure. The trailing shield 304 comprises a hot seed layer 306. Thetrailing shield 304 may comprise NiFe and the hot seed layer 306 maycomprise a high moment material, such as CoFeN or FeXN, where X includesat least one of Rh, Al, Ta, Zr, and Ti.

The main pole 302 comprises a first surface 302 a, a second surface 302b, a third surface 302 c, and a fourth surface 302 d. The main pole 302may comprise fewer or more surfaces, as the main pole 302 may have adifferent shape. The main pole 302 is surrounded by a trailing gap 322,a leading gap 324, a first side gap 308 a, and a second side gap 308 b(collectively referred to as side gap 308). The trailing gap 322 isdisposed between and in contact with the first surface 302 a of the mainpole 302 and the trailing shield 304. The leading gap 324 is disposedbelow and in contact with the fourth surface 302 d of the main pole 302.The first side gap 308 a is disposed adjacent to and in contact with thesecond surface 302 b of the main pole 302, and the second side gap 308 bis disposed adjacent to and in contact with the third surface 302 c ofthe main pole 302.

A virtual side shield (SS) 310 surrounds the first surface 302 a, thesecond surface 302 b, and the third surface 302 c of the main pole 302.The SS 310 comprises a first layer 312 and a second layer 314. The firstlayer 312 of the SS 310 surrounds the first surface 302 a, the secondsurface 302 b, and the third surface 302 c of the main pole 302. Thefirst layer 312 is disposed in the trailing gap 322 between the trailingshield 304 and the main pole 302 and adjacent to the first side gap 308a and the second side gap 308 b. The side gap 308 may comprise aninsulating material, such as alumina. A portion of the first layer 312may function as a layer of the EAMR stack 320, or the EAMR stack 320 maybe disposed around the first layer 312 in the trailing gap 322.

The second layer 314 of the SS 310 comprises a first portion 314 a and asecond portion 314 b. The first portion 314 a of the second layer 314 isdisposed adjacent to the first side gap 308 a or the second surface 302b of the main pole 302, and the second portion 314 b of the second layer314 is disposed adjacent to the second side gap 308 b or the thirdsurface 302 c of the main pole 302. The second layer 314 is in contactwith the first layer 312, and the first layer 312 is disposed betweenthe second layer 314 and the main pole 302. The second layer 314 has agreater thickness than the first layer 312. The second layer 314 mayfunction as an STL. In the magnetic recording device 300, the SS 310does not surround the main pole 302 in the leading gap 324. Aninsulating material 316 may be disposed adjacent to the second layer 314of the SS 310, such as alumina.

The first layer 312 comprises a heavy metal material, such as beta phasetungsten (β-W), platinum (Pt), or beta phase tantalum (β-Ta). Otherheavy metal materials that can be used include Hf, WHf, WIr, TeBiSb,TeBi, TeSb, Bi doped with Cu, FeMn, PfMn, IrMn, and other suitablematerials. The first layer 312 may have a thickness between about 1 nmto about 9 nm, such as about 5 nm. The second layer 314 comprises amagnetic material, such as CoFe, Coir, NiFe, or a CoFeX alloy, whereX=B, Ta, Re, or Ir. The second layer 314 may have a thickness betweenabout 2 nm to about 10 nm, such as about 5 nm. The first layer 312 andthe second layer 314 of the virtual SS 310 may together have a totalthickness between about 6 nm to about 20 nm.

In one embodiment, the first layer 312 may contact the first surface 302a of the main pole 302 (i.e., the trailing side), or a nickel oxidelayer may be disposed between the first surface 302 a of the main pole302 and the first layer 312. In another embodiment, an yttrium irongarnet (YIG) layer may be disposed between the first layer 312 and theEAMR stack 320. When current (I) is applied to the magnetic recordingdevice 300, the current flows through the first layer 312 comprising aheavy metal material. Due to the spin hall effect in the first layer312, the spins accumulated on the surface of the first layer 312 canswitch the second layer 314 and the EAMR stack 320. The switching of thevirtual SS 310 and the EAMR stack 320 may be controlled by the currentmagnitude flowing in the first layer 312.

FIG. 4 illustrates an MFS view of a magnetic recording device 400 havinga virtual side shield 410, according to one embodiment. The magneticrecording device 400 may correspond to the magnetic head assembly 121described in FIG. 1 and/or the read/write head 200 described in FIG. 2.The magnetic recording device 400 of FIG. 4 is similar to the magneticrecording device 300 of FIG. 3; however, the magnetic recording device400 does not comprise an EAMR stack disposed in the trailing gap 422.The magnetic recording device 400 may still comprise an EAMR stack (notshown) or an SOT structure disposed at another location. The magneticrecording device 400 comprises a main pole 402 and a trailing shield 404disposed above the main pole 402. The trailing shield 404 comprises ahot seed layer 406. The trailing shield 404 may comprise NiFe and thehot seed layer 406 may comprise a high moment material, such as such asCoFeN or FeXN, where X includes at least one of Rh, Al, Ta, Zr, and Ti.

The main pole 402 comprises a first surface 402 a, a second surface 402b, a third surface 402 c, and a fourth surface 402 d. The main pole 402may comprise fewer or more surfaces, as the main pole 402 may have adifferent shape. The main pole 402 is surrounded by a trailing gap 422,a leading gap 424, a first side gap 408 a, and a second side gap 408 b(collectively referred to as side gap 408). The trailing gap 422 isdisposed between and in contact with the first surface 402 a of the mainpole 402 and the trailing shield 404. The leading gap 424 is disposedbelow and in contact with the fourth surface 402 d of the main pole 402.The first side gap 408 a is disposed adjacent to and in contact with thesecond surface 402 b of the main pole 402, and the second side gap 408 bis disposed adjacent to and in contact with the third surface 402 c ofthe main pole 402.

A virtual SS 410 surrounds the first surface 402 a, the second surface402 b, and the third surface 402 c of the main pole 402. The SS 410comprises a first layer 412 and a second layer 414. The second layer 414has a greater thickness than the first layer 412. The first layer 412 ofthe SS 410 surrounds the first surface 402 a, the second surface 402 b,and the third surface 402 c of the main pole 402. The first layer 412 isdisposed in the trailing gap 422 between the trailing shield 404 and themain pole 402 and adjacent to the first side gap 408 a and the secondside gap 408 b. The side gap 408 may comprise an insulating material,such as alumina.

The second layer 414 of the SS 410 comprises a first portion 414 a and asecond portion 414 b. The first portion 414 a of the second layer 414 isdisposed adjacent to the first side gap 408 a or the second surface 402b of the main pole 402, and the second portion 414 b of the second layer414 is disposed adjacent to the second side gap 408 b or the thirdsurface 402 c of the main pole 402. The second layer 414 is in contactwith the first layer 412, and the first layer 412 is disposed betweenthe second layer 414 and the main pole 402. The second layer 414 mayfunction as an STL. In the magnetic recording device 400, the SS 410does not surround the main pole 402 in the leading gap 424. Aninsulating material 416 may be disposed adjacent to the second layer 414of the SS 410, such as alumina.

The first layer 412 comprises a heavy metal material, such as beta phasetungsten (β-W), Pt, or beta phase tantalum (β-Ta). Other heavy metalmaterials that can be used include Hf, WHf, WIr, TeBiSb, TeBi, TeSb, Bidoped with Cu, FeMn, PfMn, IrMn, and other suitable materials. The firstlayer 412 may have a thickness between about 1 nm to about 5 nm, such asabout 3 nm. The second layer 414 comprises a magnetic material, such asCoFe, Coir, NiFe, or a CoFeX alloy, where X=B, Ta, Re, or Ir. The secondlayer 414 may have a thickness between about 2 nm to about 10 nm, suchas about 5 nm. The first layer 412 and the second layer 414 of thevirtual SS 410 may together have a total thickness between about 6 nm toabout 20 nm.

In one embodiment, the first layer 412 may contact the first surface 402a of the main pole 402 (i.e., the trailing side), or a nickel oxidelayer may be disposed between the first surface 402 a of the main pole402 and the first layer 412. When current (I) is applied to the magneticrecording device 400, the current flows through the first layer 412comprising a heavy metal material. Due to the spin hall effect in thefirst layer 412, the spins accumulated on the surfaces of the firstlayer 412 can switch the second layer 414. Additionally, due to the spinhall effect in the first layer 412, the spins accumulated on thesurfaces of the first layer 412 can tilt the magnetization direction ofthe surface of the tip of the main pole 402 (i.e., the first surface 402a) to be pointing less towards the trailing shield 404, which can reducemagnetic flux from the main pole 402 to the trailing shield 404 orincrease magnetic flux from the main pole 402 to a media (i.e.,increasing the write field). The switching of the virtual SS 410 may becontrolled by the current magnitude flowing in the first layer 412.

FIGS. 5A-5C illustrate MFS views of magnetic recording devices 500, 550,570, respectively, each having a virtual side shield 510, according tovarious embodiments. Each of the magnetic recording devices 500, 550,570 may individually correspond to the magnetic head assembly 121described in FIG. 1 and/or the read/write head 200 described in FIG. 2.Each magnetic recording devices 500, 550, 570 comprises a main pole 502and a trailing shield 504 disposed above the main pole 502. The trailingshield 504 comprises a hot seed layer 506. The trailing shield 504 maycomprise NiFe and the hot seed layer 506 may comprise a high momentmaterial, such as such as CoFeN or FeXN, where X includes at least oneof Rh, Al, Ta, Zr, and Ti. Each magnetic recording devices 500, 550, 570may comprise an EAMR stack (not shown) or an SOT structure.

The main pole 502 comprises a first surface 502 a, a second surface 502b, a third surface 502 c, and a fourth surface 502 d. The main pole 502may comprise fewer or more surfaces, as the main pole 502 may have adifferent shape. The main pole 502 is surrounded by a trailing gap 522,a leading gap 524, a first side gap 508 a, and a second side gap 508 b(collectively referred to as side gap 508). The trailing gap 522 isdisposed between and in contact with the first surface 502 a of the mainpole 502 and the trailing shield 504. The leading gap 524 is disposedbelow and in contact with the fourth surface 502 d of the main pole 502.The first side gap 508 a is disposed adjacent to and in contact with thesecond surface 502 b of the main pole 502, and the second side gap 508 bis disposed adjacent to and in contact with the third surface 502 c ofthe main pole 502.

Each of the magnetic recording devices 500, 550, 570 further comprises avirtual SS 510 surrounding the second surface 502 b, the third surface502 c, and the fourth surface 502 d of the main pole 502. The SS 510comprises a first layer 512 and a second layer 514 in contact with oneor more surfaces of the first layer 512, and the first layer 512 isdisposed between the second layer 514 and the main pole 502. The secondlayer 514 has a greater thickness than the first layer 512. The secondlayer 514 may function as an STL. The first layer 512 surrounds thesecond surface 502 b, the third surface 502 c, and the fourth surface502 d of the main pole 502. The first layer 512 is disposed in theleading gap 424 and adjacent to the first side gap 508 a and the secondside gap 508 b. The side gap 508 may comprise an insulating material,such as alumina. The SS 510 does not surround the main pole 502 in thetrailing gap 522.

In each magnetic recording device 500, 550, 570, the first layer 512comprises a heavy metal material, such as beta phase tungsten (β-W), Pt,or beta phase tantalum (β-Ta). Other heavy metal materials that can beused include Hf, WHf, WIr, TeBiSb, TeBi, TeSb, Bi doped with Cu, FeMn,PfMn, IrMn, and other suitable materials. The first layer 512 may have athickness between about 1 nm to about 9 nm, such as about 3 nm to about5 nm. The first layer 512 and the second layer 514 of the virtual SS 510may together have a total thickness between about 6 nm to about 20 nm.An insulating material 516 may be disposed adjacent to the second layer514 of the SS 510, such as alumina.

When current (I) is applied to each of the magnetic recording devices500, 550, 570, the current flows through the first layer 512 comprisinga heavy metal material. Due to the spin hall effect in the first layer512, the spins accumulated on the surfaces of the first layer 512 canswitch the second layer 514. The switching of the virtual SS 510 may becontrolled by the current magnitude flowing in the first layer 512.

In the magnetic recording device 500 of FIG. 5A, the second layer 514comprises a first portion 514 a and a second portion 514 b. The firstportion 514 a of the second layer 514 is in contact with the first sidegap 508 a and disposed adjacent to the second surface 502 b of the mainpole 502, and the second portion 514 b of the second layer 514 is incontact with the second side gap 508 b and disposed adjacent to thethird surface 502 c of the main pole 502. In the magnetic recordingdevice 500, the second layer 514 is not disposed in the leading gap 524adjacent to the fourth surface 502 d of the main pole 502 or in thetrailing gap 522 adjacent to the first surface 502 a of the main pole502. Thus, in the magnetic recording device 500, only the first layer512 is disposed in the leading gap 524.

In the magnetic recording device 500 of FIG. 5A, the first portion 514 aand the second portion 514 b of the second layer 514 comprise the samematerial and have the same thickness. The first portion 514 a and thesecond portion 514 b of the second layer 514 may each comprise amagnetic material, such as CoFe, Colr, NiFe, or a CoFeX alloy, whereX=B, Ta, Re, or Ir. The first portion 514 a and the second portion 514 bof the second layer 514 may each have a thickness between about 2 nm toabout 10 nm, such as about 5 nm.

In the magnetic recording device 550 of FIG. 5B, the second layer 514surrounds the second surface 502 b, the third surface 502 c, and thefourth surface 502 d of the main pole 502. The second layer 514 isdisposed in the leading gap 524 and adjacent to the first side gap 508 aand the second side gap 508 b. In other words, the second layer 514 isdisposed adjacent to the second surface 502 b, the third surface 502 c,and the fourth surface 502 d of the main pole 502.

In the magnetic recording device 550 of FIG. 5B, the second layer 514 isone continuous layer (i.e., not comprised of portions, or comprised ofthree portions seamlessly coupled together to form one layer). Thus, inthe magnetic recording device 550, the first layer 512 and the secondlayer 514 both surround the second surface 502 b, the third surface 502c, and the fourth surface 502 d of the main pole 502. The second layer514 may comprise a magnetic material, such as CoFe, Colr, NiFe, or aCoFeX alloy, where X=B, Ta, Re, or Ir. The second layer 514 may have athickness between about 5 nm to about 12 nm, such as about 10 nm.

In the magnetic recording device 570 of FIG. 5C, the second layer 514comprises a first portion 514 a, a second portion 514 b, and a thirdportion 514 c. The second layer 514 in the magnetic recording device 570of FIG. 5C is discontinuous, as compared to the continuous second layer514 in the magnetic recording device 550 of FIG. 5B. The first portion514 a of the second layer 514 is disposed adjacent to the first side gap508 a and the second surface 502 b of the main pole 502, the secondportion 514 b of the second layer 514 is disposed adjacent to the secondside gap 508 b and the third surface 502 c of the main pole 502, and thethird portion 514 c of the second layer 514 is disposed in the leadinggap 524 and adjacent to the fourth surface 502 d of the main pole 502.Thus, in the magnetic recording device 570, the first layer 512 and thesecond layer 514 both surround the second surface 502 b, the thirdsurface 502 c, and the fourth surface 502 d of the main pole 502.

In the magnetic recording device 570 of FIG. 5C, the first portion 514 aand the second portion 514 b of the second layer 514 may comprise thesame material while the third portion 514 c comprises a differentmaterial than the first and second portions 514 a, 514 b. The firstportion 514 a and the second portion 514 b of the second layer 514 mayeach comprise a magnetic material, such as CoFe, Colr, NiFe, or a CoFeXalloy, where X=B, Ta, Re, or Ir. The third portion 514 c of the secondlayer 514 may also comprise a magnetic material, such as CoFe, Coir,NiFe, or a CoFeX alloy, where X=B, Ta, Re, or Ir, so long as thematerial of the third portion 514 c is different than the material ofthe first and second portions 514 a, 514 b. In one embodiment, each ofthe first, second, and third portions 514 a-514 c comprise a differentmagnetic material. The first portion 514 a, the second portion 514 b,and the third portion 514 c of the second layer 514 may each have thesame thickness. The first portion 514 a, the second portion 514 b, andthe third portion 514 c of the second layer 514 may each have athickness between about 2 nm to about 10 nm, such as about 5 nm.

FIG. 6 illustrates an MFS view of a magnetic recording device 600 havinga virtual side shield 610, according to one embodiment. The magneticrecording device 600 may correspond to the magnetic head assembly 121described in FIG. 1 and/or the read/write head 200 described in FIG. 2.The magnetic recording device 600 may comprise an EAMR stack (not shown)or an SOT structure. The magnetic recording device 600 comprises a mainpole 602 and a trailing shield 604 disposed above the main pole 602. Thetrailing shield 604 comprises a hot seed layer 606. The trailing shield604 may comprise NiFe and the hot seed layer 606 may comprise a highmoment material, such as such as CoFeN or FeXN, where X includes atleast one of Rh, Al, Ta, Zr, and Ti.

The main pole 602 comprises a first surface 602 a, a second surface 602b, a third surface 602 c, and a fourth surface 602 d. The main pole 602may comprise fewer or more surfaces, as the main pole 602 may have adifferent shape. The main pole 602 is surrounded by a trailing gap 622,a leading gap 624, a first side gap 608 a, and a second side gap 608 b(collectively referred to as side gap 608). The trailing gap 622 isdisposed between and in contact with the first surface 602 a of the mainpole 602 and the trailing shield 604. The leading gap 624 is disposedbelow and in contact with the fourth surface 602 d of the main pole 602.The first side gap 608 a is disposed adjacent to and in contact with thesecond surface 602 b of the main pole 602, and the second side gap 608 bis disposed adjacent to and in contact with the third surface 602 c ofthe main pole 602. The side gap 608 may comprise an insulating material,such as alumina.

A virtual SS 610 surrounds the second surface 602 b, the third surface602 c, and the fourth surface 602 d of the main pole 602. The SS 610comprises a first layer 612 and a second layer 614. The second layer 614is in contact with the first layer 612, and the first layer 612 isdisposed between the second layer 614 and the main pole 602. The secondlayer 614 has a greater thickness than the first layer 612. The firstlayer 612 and the second layer 614 of the virtual SS 610 may togetherhave a total thickness between about 2 nm to about 12 nm. The secondlayer 614 may function as an STL.

The first layer 612 of the SS 610 comprises a first portion 612 a, asecond portion 612 b, a third portion 612 c, a fourth portion 612 d, afifth portion 612 e, a sixth portion 612 f, and a seventh portion 612 g(collectively referred to as the first layer 612). The portions 612a-612 g of the first layer 612 form one continuous layer. The firstportion 612 a is disposed adjacent to a first insulating material 616 a.The second portion 612 b is coupled to the first portion 612 a and isdisposed adjacent to the trailing gap 622. The third portion 612 c iscoupled to the second portion 612 b and is disposed adjacent to thefirst side gap 608 a. The fourth portion 612 d is coupled to the thirdportion 612 c and is disposed adjacent to the leading gap 624. The fifthportion 612 e is coupled to the fourth portion 612 d and is disposedadjacent to the second side gap 608 b. The sixth portion 612 f iscoupled to the fifth portion 612 e and is disposed adjacent to thetrailing gap 622. The seventh portion 612 g is coupled to the sixthportion 612 f and is disposed adjacent to a second insulating material616 b. Together, the first through seventh portions 612 a-612 g of thefirst layer 612 are arranged in an inverted “W” shape.

The second layer 614 of the SS 610 comprises a first portion 614 a, asecond portion 614 b, a third portion 614 c, a fourth portion 614 d, anda fifth portion 614 e. The first portion 614 a of the second layer 614is disposed between and in contact with the first portion 612 a of thefirst layer 612 and a third insulating material 616 c. The secondportion 614 b of the second layer 614 is disposed between and in contactwith the third portion 612 c of the first layer 612 and the thirdinsulating material 616 c. The third portion 614 c of the second layer614 is coupled to the second portion 614 b of the second layer 614 andis disposed adjacent to the leading gap 624. The fourth portion 614 d ofthe second layer 614 is coupled to the third portion 614 c of the secondlayer 614 and is disposed between and in contact with the fifth portion612 e of the first layer 612 and a fourth insulating material 616 d. Thefifth portion 614 e of the second layer 614 is disposed between and incontact with the seventh portion 612 g of the first layer 612 and thefourth insulating material 616 d.

The first portion 614 a is spaced a first distance 626 from the secondportion 614 b. The first distance 626 may be about 15 nm to about 25 nm,such as about 20 nm. Thus, the first portion 612 a of the first layer612 is spaced from the third portion 612 c of the first layer 612 by thefirst distance 626 and the first and second portions 614 a, 614 b of thesecond layer 614. The fourth portion 614 d is spaced a second distance628 from the fifth portion 614 e. The second distance 628 may be about15 nm to about 25 nm, such as about 20 nm. The first distance 626 may bethe same as the second distance 628. The fifth portion 612 e of thefirst layer 612 is spaced from the seventh portion 612 g of the firstlayer 612 by the second distance 628 and the fourth and fifth portions614 d, 614 e of the second layer 614.

The first, second, third, and fourth insulating materials 616 a, 616 b,616 c, 616 d may each comprise alumina. The first insulating material616 a may be coupled to the third insulating material 616 c in theleading gap 624, and the second insulating material 616 b may be coupledto the fourth insulating material 616 d in the leading gap 624. Thethird insulating material 616 c may be disposed in the first side gap608 a such that the third insulating material 616 c forms a portion ofthe first side gap 608 a. Similarly, the fourth insulating material 616d may be disposed in the second side gap 608 b such that the fourthinsulating material 616 d forms a portion of the second side gap 608 b.

The first layer 612 comprises a heavy metal material, such as beta phasetungsten (β-W), Pt, or beta phase tantalum (p-Ta). Other heavy metalmaterials that can be used include Hf, WHf, WIr, TeBiSb, TeBi, TeSb, Bidoped with Cu, FeMn, PfMn, IrMn, and other suitable materials. The firstlayer 412 may have a thickness between about 1 nm to about 6 nm, such asabout 3 nm. The second layer 614 comprises a magnetic material, such asCoFe, Coir, NiFe, or a CoFeX alloy, where X=B, Ta, Re, or Ir. The secondlayer 614 may have a thickness between about 1 nm to about 9 nm, such asabout 5 nm. In one embodiment, the third portion 614 c of the secondlayer 614 comprises a different material than the first, second, fourth,and fifth portions 614 a, 614 b, 614 d, 614 e. In another embodiment,each portion 614 a-614 e of the second layer 614 comprises the samematerial.

When current (I) is applied to the magnetic recording device 600, thecurrent flows through the first layer 612 comprising a heavy metalmaterial. Due to the spin hall effect in the first layer 612, the spinsaccumulated on the surfaces of the first layer 612 can switch the secondlayer 614. The switching of the virtual SS 610 may be controlled by thecurrent magnitude flowing in the first layer 612.

FIG. 7 illustrates a cross-sectional view of an exemplary magneticrecording device 700 illustrating the effects of a virtual side shield710, according to one embodiment. The magnetic recording device 700 maycorrespond to the magnetic head assembly 121 described in FIG. 1 and/orthe read/write head 200 described in FIG. 2. The magnetic recordingdevice 700 may be the magnetic recording device 300 of FIG. 3, themagnetic recording device 400 of FIG. 4, the magnetic recording device500 of FIG. 5A, the magnetic recording device 550 of FIG. 5B, themagnetic recording device 570 of FIG. 5C, or the magnetic recordingdevice 600 of FIG. 6.

The magnetic recording device 700 comprises a main pole 702 disposedabove a media 730 and a virtual SS 710 comprising a first layer 712 anda second layer 714. The virtual SS 710 surrounds at least one surface ofthe main pole 702. In some embodiments, the virtual SS 710 surrounds atleast two surface of the main pole 702. The configuration of the firstlayer 712 and the second layer 714 of the SS 710 may be like the SS 310of FIG. 3, the SS 410 of FIG. 4, the SS 510 of FIGS. 5A-5C, or the SS610 of FIG. 6. The magnetic recording device 700 may comprise otherelements not shown in FIG. 7, such as a trailing shield and an EAMRstack.

As shown in FIG. 7, when a bias current is applied to the first layer712, the second layer 714 can be switched with a magnetization directionopposite to the magnetization direction in the main pole 702. As aresult, the charges coming off of the main pole 702 cancel out thecharges coming off of the SS 710 at the media 730. Thus, adjacent trackson the media 730 are no longer erased. Moreover, no magnetic shuntingoccurs in the side gaps 708. The magnetic recording device 700 has anincreased BPI and overwrite capability as compared to conventionalmagnetic recording devices. The magnetic recording device 700 furtherexperiences a similar TPI and adjacent track interference (ATI) as aconventional magnetic recording device, and has an improved ADC ascompare to conventional magnetic recording devices.

Therefore, utilizing a virtual side shield in a magnetic recordingdevice, like shown in FIGS. 3-7, eliminates magnetic shunting andprevents erasure of adjacent tracks on a media when writing to themedia. As such, the above-described magnetic recording devicescomprising a virtual side shield surrounding two or more surfaces of amain pole have increased ADC, BPI, and overwrite capabilities withoutsacrificing TPI and ATI capabilities.

In one embodiment, a magnetic recording device comprises a main polehaving a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, and a sideshield surrounding one or more of the first surface, the second surface,the third surface, and the fourth surface of the main pole, including atleast one of the second surface and the third surface, wherein the sideshield comprises a first layer comprising a heavy metal material, and asecond layer comprising a magnetic material, wherein the second layerhas a greater thickness than the first layer, and wherein the firstlayer and the second layer have a total thickness between about 2 nm toabout 20 nm.

The magnetic recording device further comprises a first side gapdisposed adjacent to the second surface of the main pole, a second sidegap disposed adjacent to the third surface of the main pole, a trailingshield disposed above the first surface of the main pole and the one ormore side gaps, a trailing gap disposed between the first surface of themain pole and the trailing shield, and a leading gap disposed adjacentto the fourth surface of the main pole. The first layer of the sideshield surrounds the second surface, the third surface, and the fourthsurface of the main pole. The second layer of the side shield comprisesa first portion disposed adjacent to the first side gap and a secondportion disposed adjacent to the second side gap. The first layer isdisposed between the first and second side gaps and the second layer.The second layer of the side shield further comprises a third portiondisposed adjacent to the leading gap.

The first layer comprises a first portion, a second portion, a thirdportion, a fourth portion, a fifth portion, a sixth portion, and aseventh portion. The second layer further comprises a third portion, afourth portion, and a fifth portion. The first layer of the side shieldis in contact with the first side gap, the second side gap, and thetrailing gap, the first layer surrounding the first surface, the secondsurface, and the third surface of the main pole. The second layer of theside shield is in contact with the first layer, the second layercomprising a first portion disposed adjacent to the first side gap and asecond portion disposed adjacent to the second side gap.

In another embodiment, a magnetic recording device comprises a main polehaving a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, a trailingshield disposed adjacent to the trailing gap, and a side shieldcomprising a first layer surrounding the first surface, the secondsurface, and the third surface of the main pole, and a second layersurrounding the second surface and the third surface of the main pole.

The first layer comprises beta phase tungsten (β-W), Pt, or beta phasetantalum (β-Ta), and wherein the second layer comprises CoFe, Colr,NiFe, or a CoFeX alloy where X=B, Ta, Re, or Ir. The first layer has athickness between about 1 nm to about 9 nm, and the second layer has athickness between about 2 nm to about 10 nm. The magnetic recordingdevice further comprises an energy assisted-magnetic recording stackdisposed between the main pole and the trailing shield.

In yet another embodiment, a magnetic recording device comprises a mainpole having a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap, a trailingshield disposed adjacent to the trailing gap, one or more side gapsdisposed below the trailing shield and surrounding the second and thirdsurfaces of the main pole, and a side shield surrounding the secondsurface, the third surface, and the fourth surface of the main pole, theside shield comprising a first layer in contact with the one or moreside gaps and a second layer in contact with the first layer, whereinthe side shield is spaced from the trailing shield and the main pole.

The first layer comprises beta phase tungsten (β-W), Pt, or beta phasetantalum (β-Ta). The first layer has a thickness between about 1 nm toabout 9 nm. The second layer comprises CoFe, Coir, NiFe, or a CoFeXalloy where X=B, Ta, Re, or Ir. The second layer has a thickness betweenabout 2 nm to about 10 nm. The second layer comprises a first portiondisposed adjacent to a first side gap of the one or more side gaps andthe second surface of the main pole and a second portion disposedadjacent to a second side gap of the one or more side gaps and the thirdsurface of the main pole. The second layer further comprises a thirdportion disposed adjacent to a leading gap and the fourth surface of themain pole. The third portion of the second layer comprises a differentmaterial than the first portion and the second portion of the secondlayer.

The first layer of the side shield surrounds the second surface, thethird surface, and the fourth surface of the main pole. The second layerof the side shield surrounds at least the second surface and the thirdsurface of the main pole. The first layer comprises a first portion, asecond portion, a third portion, a fourth portion, a fifth portion, asixth portion, and a seventh portion. The second layer comprises a firstportion, a second portion, a third portion, a fourth portion, and afifth portion.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A magnetic recording device, comprising: a mainpole having a first surface adjacent to a trailing gap, a second surfaceadjacent to the first surface, a third surface opposite the secondsurface, and a fourth surface adjacent to a leading gap; a trailingshield disposed adjacent to the trailing gap; one or more side gapsdisposed below the trailing shield and surrounding the second and thirdsurfaces of the main pole; and a side shield surrounding the secondsurface, the third surface, and the fourth surface of the main pole, theside shield comprising a first layer in contact with the one or moreside gaps and a second layer in contact with the first layer, whereinthe side shield is spaced from the trailing shield and the main pole,wherein the first layer comprises a first portion, a second portion, athird portion, a fourth portion, a fifth portion, a sixth portion, and aseventh portion, and wherein the second layer comprises a first portion,a second portion, a third portion, a fourth portion, and a fifthportion.
 2. The magnetic recording device of claim 1, wherein the firstportion of the second layer is spaced from the second portion of thesecond layer by a first distance between about 15 nm to about 25 nm. 3.The magnetic recording device of claim 2, wherein the fourth portion ofthe second layer is spaced a second distance from the fifth portion ofthe second layer by a second distance, wherein the first distance issubstantially equal to the second distance.
 4. The magnetic recordingdevice of claim 1, further comprising a hot seed layer disposed betweenthe trailing shield and the trailing gap, wherein the hot seed layercomprises CoFeN or FeXN, where X includes at least one of Rh, Al, Ta,Zr, and Ti.
 5. The magnetic recording device of claim 1, wherein thesecond layer comprises beta phase tungsten (β-W), Pt, beta phasetantalum (β-Ta), Hf, WHf, WIr, TeBiSb, TeBi, TeSb, Bi doped with Cu,FeMn, PfMn, and IrMn.
 6. The magnetic recording device of claim 1,wherein the first layer comprises a magnetic material, such as CoFe,Coir, NiFe, or a CoFeX alloy, where X=B, Ta, Re, or Ir.
 7. The magneticrecording device of claim 1, wherein the third portion of the firstlayer comprises a different material than the first, second, fourth, andfifth portions.
 8. The magnetic recording device of claim 1, whereineach portion of the first layer comprises the same material.
 9. Themagnetic recording device of claim 1, wherein the trailing shieldcomprises NiFe.
 10. The magnetic recording device of claim 1, whereinthe first portion of the second layer and the second portion of thesecond layer are disposed between the first portion of the first layerand the third portion of the first layer.
 11. The magnetic recordingdevice of claim 10, wherein the first portion of the second layer andthe second portion of the second layer are spaced apart by a distance ofbetween about 15 nm and about 25 nm.
 12. The magnetic recording deviceof claim 11, wherein the first portion of the second layer and thesecond portion of the second layer are spaced apart by an insulatingmaterial.
 13. The magnetic recording device of claim 1, wherein thefourth portion of the second layer and the fifth portion of the secondlayer are disposed between the fifth portion of the first layer and theseventh portion of the first layer.
 14. The magnetic recording device ofclaim 13, wherein the fourth portion of the second layer and the fifthportion of the second layer are spaced apart by a distance of betweenabout 15 nm and about 25 nm.
 15. The magnetic recording device of claim14, wherein the fourth portion of the second layer and the fifth portionof the second layer are spaced apart by an insulating material.
 16. Themagnetic recording device of claim 1, further comprising a hot seedlayer disposed between the trailing shield and the trailing gap, whereinthe second portion of the first layer faces the hot seed layer.
 17. Themagnetic recording device of claim 16, further comprising a hot seedlayer disposed between the trailing shield and the trailing gap, whereinthe sixth portion of the first layer faces the hot seed layer.
 18. Themagnetic recording device of claim 1, wherein the second layer has athickness of between about 1 nm and about 9 nm.
 19. The magneticrecording device of claim 18, wherein the first layer has a thickness ofbetween about 1 nm and about 6 nm.
 20. A data storage device comprisingthe magnetic recording device of claim 1.